Recently, the right tube of the Erli Village Tunnel, a key control project of the Jiuzhaigou–Mianyang Expressway in Sichuan Province, was holed through, laying a solid foundation for the opening of the entire line to traffic.

The expressway from Jiuzhaigou (Sichuan–Gansu border) to Mianyang is a component of the G8513 Pingliang–Mianyang Expressway, with a total length of 259 km. The Erli Village Tunnel (formerly Shuiniujia Tunnel), 6,063 m long, is an extra-long tunnel in unfavorable geological conditions and the tunnel with the highest construction risk on the entire line. The tunnel passes through 10 fracture zones in total, with more than 90% of its length in Grade V weak surrounding rock, which is characterized by low strength, easy softening upon contact with water, poor self-stability and large deformation, making soft-rock large deformation highly likely during construction. The exit end of the Erli Village Tunnel is 3,967 m long and passes through 6 fracture zones, all in Grade V weak surrounding rock, involving great construction difficulty, high safety risk and stringent technical requirements. Due to limited site conditions, the inclined shaft, which serves as the **transport passage for tunnel excavation, lies entirely within a fracture zone and repeatedly encountered water inflow and collapse during construction.

During construction, the project team carried out a series of technical research efforts targeting the tunnel's special geological conditions and the key and difficult points of construction. The inclined shaft was constructed using the "advanced middle pipe roof + micro-bench method", and the construction method for the main tunnel was optimized to the "double-layer advanced small conduit + three-bench method with reserved core soil". Technologies such as advanced probe holes, advanced geological forecasting and in-hole inspection of advanced boreholes were actively applied, enabling the successful passage through the fault fracture zones. On this basis, the project undertook one bureau-level research topic and obtained 6 authorized national utility model patents and 3 provincial/ministerial-level QC achievements.

Once completed, the Jiuzhaigou–Mianyang Expressway will become a north–south rapid corridor between Sichuan and Gansu provinces, and together with the route from Chengdu via Dujiangyan, Wenchuan and Songpan to Jiuzhaigou, it will jointly form the Jiuhuan Line, the golden tourism route of Sichuan Province, creating a new outbound passage from Sichuan. By then, the drive from Chengdu to Jiuzhaigou will be shortened from 8 hours to 4 hours.